I've been riding both scooters and motorcyles of various types since I was 13, so let me chime in with my advice:
As Pelihu said, the small scooters are quite useful for moving around campus or on minor roads. If it's a 50cc, then you'll probably be limited to 30 - 40 mph. If it's a bigger scooter (125 cc+) , then you may be upto speed in slow-ish motorways. For keeping up with 70+ traffic, you'll need a 250+cc scooter. Appropriate dressing is recommended (see safety issues).
you can get the smaller ones by about a grand (new Chinese made or European/Japanese second-hand ones). But as you move up the food chain, you are venturing into used car prices territory. A vintage Vespa in good condition will cost a lot, though. Scooters are typically cheaper to maintain and fill up than cars, specially smaller ones.
c) Safety issues:
scooters are very easy to operate and it's quite difficult to fall from a scooter, unless you are hit by another vehicle. The problem is, most vehicles won't see you and the ones that do, won't cut you any slack. That's why they are better suited to minor roads and streets with little traffic rather than major roads. Most people who ride scooters don't wear any safety gear apart from a helmet. I, however, recommend full safety gear (i.e.: bike jacket and bike pants, full-face helmet, riding gloves and boots) even on scooters. While gear won't protect you in the event of hitting a fix object, they do address the skin abrasion that ensues when you fall. Proper gear is made for bikes, fashion leather won't stand pavement abrasion and neither will jeans. I understand you can ride a scooter with a car driver's licence in the US, although don't quote me on this.
2) Small motorcycles:
Most small motorcycles are on or above 125 cc, and most are capable-ish at highway speeds. You'll need to master the left hand clutch-lever, left foot gear lever, right hand front brake and right foot back brake controls to ride any of these. Don't worry, it sounds more difficult than it actually is. You'll need a licence to ride these and, while not mandatory, I'll recommend you get training such as:
The basic motorcycle types in the small bikes group (categories multiply as you increase engine size) are:
Standards: as the name indicates, they are basic motorcycles. Not much specialization nor wind protection. Riding position is up-right. Typical example: Honda Nighthawk 250.
Trail bikes: these are styled like moto-crossers, but they are less capable off-road in exchange for milder manners on road and longer service intervals. Riding position is up-right and seats are a bit higher than in standards. Eg: Yamaha XT225, Kawasaki KLR250.
Customs - cruisers: styled like their bigger customs - cruisers brothers (i.e.: Harleys and Harley rip-offs) but usually way lighter and smaller. Riding position is laid back and seat heights are very low. Eg: Yamaha Virago 250, Honda Rebel 250, Kawasaki Eliminator 125. Get one with a V-twin engine layout rather than a single or parallel twin for extra street - cred! Note: most custom bikes riders neglect the use of protective gear, except for the mandatory helmet. And most ride with open face helmets (which will protect the back of your head but not the front). While the bikes in these category are usually mild mannered and arguably less dangerous, I'd still recommend proper gear when riding any bike.
Sports bikes: the bigger bikes in this category are the so-called crotch-rockets or race-replicas and they are best left to experienced riders. The only beginner friendly bike in this category is the Kawasaki Ninja 250. It can properly manage highway riding while nurturing your skills without the dangers of too much power. They are cheap to maintain, easy to buy and easier to sell. Used ones with less than 1k miles will cost about 2.5 grand and a brand new one costs 3k (+taxes and other charges) from Kawasaki.
There's excellent advice for new riders here:
Budget about 2k for an old-ish Ninja 250 or any of the trail bikes. Budget a bit more for the Nighthawk or a custom. Proper maintenance is required (not only oil changes but valve- clearance checks and other things every 5k miles or so).
Main issues to consider:
- type of route you'll take.
- whether you'd be willing to put on proper gear everyday.
I, personally, intend to buy a Ninja 250 or a similar bike to ride in Boston and venture occasionally into nearby areas.
Hope it helps. Let me know if you have any further questions.